Gas turbine engines are often used in aircraft, among other applications. For example, gas turbine engines used as aircraft main engines not only provide propulsion for the aircraft, but in many instances may also be used to drive various other rotating components such as, for example, generators, compressors, and pumps, to thereby supply electrical, pneumatic, and/or hydraulic power.
Generally, a gas turbine engine includes a combustor, a power turbine, and a compressor. During operation of the engine, the compressor draws in ambient air, compresses it, and supplies compressed air to the combustor. The compressor also typically includes a diffuser that diffuses the compressed air before it is supplied to the combustor. The combustor receives fuel from a fuel source and the compressed air from the compressor, and supplies high energy compressed air to the power turbine, causing it to rotate. The power turbine includes a shaft that may be used to drive the compressor.
The compressor of a gas turbine engine can take the form of an axial compressor, a centrifugal compressor, or some combination of both (i.e., an axial-centrifugal compressor). In an axial compressor, the flow of air through the compressor is at least substantially parallel to the axis of rotation. In a centrifugal compressor, the flow of air through the compressor is turned at least substantially perpendicular to the axis of rotation. An axial-centrifugal compressor includes an axial section (in which the flow of air through the compressor is at least substantially parallel to the axis of rotation) and a centrifugal section (in which the flow of air through the compressor is turned at least substantially perpendicular to the axis of rotation). While gas turbine engines are generally effective, in certain situations there may be a desire for improved efficiency of gas turbine engines, for example in gas turbine engines with axial-centrifugal compressors.
Accordingly, there is a need for an improved axial-centrifugal compressor for a gas turbine engine, for example that results in increased efficiency for the gas turbine engine. There is also a need for an improved gas turbine engine with an improved axial-centrifugal compressor that provides increased efficiency for the gas turbine engine. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.